Scientific American 201905

May 2019, ScientificAmerican.com 35

can’t clot and is full of im mune agents, but we don’t
know much about what they do.” It is also unclear why
we shed this biological tissue so dramatically when
most mammals that experience estrus appear to reab­
sorb their endometrial linings at the end of each cycle.
Even less is known about why so many women—up to
80  percent by some estimates—experience cramps,
bloating, fatigue, anger or other symptoms just before
the on set of menstruation. “We know so little about
menstruation,” says Tomi­Ann Roberts, president of
the Society for Menstrual Cycle Research and a profes­
sor of psychology at Colorado College, and what scien­
tists do know is often badly communicated with the
public. “Because of this, our attitudes toward menstru­
ation are overwhelmingly negative. This has real con­
sequences for how we can begin to un derstand healthy
menstruation, as well as menstruation­re lated disor­
ders and the treatment op tions available.”

MASKING MENSTRUATION
the taBoo has taken many forms. In 1920 a Hungari­
an­born pediatrician working in Vienna named Béla
Schick published a collection of anecdotal observa­
tions: When he asked a menstruating woman to han­
dle flowers, they wilted within minutes. When he
compared the bread dough made by several women,
the loaf made by the one having her period rose
22  percent less. Schick concluded that menstrual
blood contained a kind of poison. By the early 1950s
Harvard University scientists were referring to “meno­
toxins” and injecting menstrual blood into animals to
observe the effects. Some of those animals died, most
likely be cause the blood samples carried bacteria and
other contaminants. Not much came of these experi­
ments in terms of useful data, but the notion that
menstrual blood contains mysterious and even dan­
gerous properties has persisted in the scientific litera­
ture and our cultural imagination.
By the late 1950s research around menstruation
had shifted to center almost entirely on preventing
unplanned pregnancies at a time when maternal and
infant mortality was troublingly high, especially in
poor communities. In 1923 Margaret Sang er, the activ­
ist, nurse and founder of the organizations that would
later become Planned Parenthood, wrote that “Birth
Control means liberation for women and for men.” In
1951 she met a physiologist named Gregory Pincus,
who had performed what was considered at the time
to be the first in vitro fertilization of rabbits. With
Sanger securing funding, Pincus set up a lab to test
formulations of synthetic versions of hormones that
regulate the menstrual cycle and teamed up with John
Rock, a Boston obstetrician­gynecologist, to run clini­
cal trials of the drug.
After a study of almost 60 women in and around
Boston, Pincus and Rock turned to Puerto Rico to run
the first large­scale trial of the drug that the U.S. Food
and Drug Administration would approve in 1960 as the
first oral contraceptive. They recruited 265 Puerto Rican

women, many of them poor, to the study without the

level of “informed consent” required today. Twenty­two

percent of the participants dropped out after reporting

side effects such as nausea, dizziness, headaches and

vomiting. The study’s medical director argued that the

pill “caused too many side reactions to be generally

acceptable.” Nevertheless, it went to market.

The pill was, of course, celebrated as a huge break­

through. “It was the first form of birth control sepa­

rate from sex that women could completely control,”

notes Elizabeth Kissling, a professor of women and

gender studies at Eastern Washington University. It is

impossible to overstate the freedom the pill represent­

ed for women, whose reproductive lives were other­

wise largely under male control. But liberation came

with a price. By the late 1960s patients across the U.S.

were reporting the same symptoms documented dur­

ing the Puerto Rican trial. Despite many reformula­

tions over the ensuing de cades, side effects remain a

problem for many women on the pill; risks for breast

cancer, blood clots and stroke may also be higher. In

their quest to bring reproductive freedom to women,

Sanger, Pincus and Rock appear to have ignored the

implications of shutting down a woman’s natural cycle,

Kissling explains. In other words, scientists figured

out how to supplant periods long before they began

MENSTRUAL

CUPS can be

a reusable,

environmentally

friendly alterna-

tive to tampons

and pads.

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